According to the founder of AdDuplex, Alan Mendelevich@ailon, today in Twiitter, revealed that the Nokia Lumia 520/521 as the number one Windows Phone best seller worldwide. With more high-end phones available from Nokia and also other Windows Phone makers, it is quite surprising that this variant of Lumia to snatch the top spot in term of sales around the world.
He also mentioned that the Lumia 525 which is a newcomer with similar spec with the 52x variants, but with upgraded RAM of 1GB is placed at 19th, the Lumia 1520, the first Windows Phone with 2GB of RAM at 16th, and the Lumia 1020, the 6-lens 41 Megapixel powered Windows Phone at the 11th place. 
The Nokia Lumia 920 which is the first version of Windows Phone that featured Pureview technology  is the second most used smartphone in the USA 
Looks like Microsoft and Nokia’s effort of introducing high-end phones are still not as effective as their low-end and mid-end handsets in terms of sales, which usually higher-end phones would be top of the chart if compared with how Android and iOS devices compete globally. 
What should Microsoft and Nokia do in order to boost Windows Phone sales? Should they remain with their current pattern of sales for the Windows Phone and start focusing on Android based phones?

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